The present invention relates to an image processing apparatus and its method suitably used when a user specifies a region of interest (ROI) on volume data.
Volume segmentation is image processing that splits volume data obtained using, e.g., CT (Computerized Tomography) or MRI (Magnetic Resonance Imaging) into several visually perceptual or semantic units. This volume segmentation is indispensable for obtaining useful information such as shape or cubic volume from unprocessed volume data and therefore has been studied for about thirty years. However, no fully automated method is yet available. This is because that high level information processing that covers a wide range of information from low-dimensional information such as edge detection and texture analysis to high-dimensional information such as the entire shape or topology of an object is required in order to obtain a segmentation result that a user expects. In particular, it is thought that it is impossible to automatically generate the high-order information without user's instruction.